Surgical knife



' May 12, 1931.

A. A. s. STUART SURGICAL KNIFE Filed May. 31, 1950 INVENTOR ALEXANDER A. S. STUART 11 is ATTORN EYS V "and substantially flat and is pre Patented May 12, 1931 ALEXANDER A. s. STUART, QEEIDGEEIELD PARKyNEW JERSEY SURGICAL KNIFE Application filed May 31,

. This invention relates to surgical knives having detachable blades. Important objects of the invention are, to provide such a knife of improved and simplified design, and to provide a knife designed to facilitate the attachment and detachment of its blade. In the drawings, Fig. 1 is aside elevation of the knife; I

Fig. 2an edge view of the knife; Fig. 3 an enlarged side view, partly in section, showing the mounting of the blade shank in the handle socket- Fig. 4 a view similarto Fig. 3 showing the knife blade in a reversed position; Fig. 5 a-v'iew siniilarto Fig. 3 showing the blacile shank partly inserted into the socket; Fig. 6 a transverse section taken on the line 66 ofFig.'3.

The knife structure includesa handle 1 anda blade 2. The handle'is straight, thin ferably formed of one piece of suitablemetal. At one endit is hollowed out to form a longitudinal socket 3 which 'definesa straight, flat, inwardly extending passage 4 terminating in a flat, circular, milled out cavity 5. Said cavity is centered with relation to the passage 41 and its diameter is greater than the width ofthe latter sothat two forwardly converging, concave locking shoulders 6 are 7 formed at opposite edges of thesocket. An elongated, substantially V-shaped cleft 7 is formed in the socket end of "the handle and extends straight inward. This cleft is cut transversely to the plane of the blade and extends through the sides of the handle at opposite sides of the socket. Its inner end ter- 'minatesnear the-center of the cavity 5 and is rounded- At the opposite edges of the socket entrance the handle is formed with outwardly beveled or flared shouldersB. V

The knife bladeQhas an integral shank 9 and is preferably formed of thin sheet metal stock. For most of its length the shank is bifurcated by forming a straight, longitudinal slot 10 runningcentrallv' through the shank and having an enlarged rounded end .11. -Said slot divides the shank into two shoulders 6. 1 The expandingtendency of the to press firmly against the opposite wallsof [spring fingers 12 and 13. Finger 12 has a 1930. Serial No. 458,019.

straight longitudinal edge and is outwardly rounded at its free end. The outer longitudinal edge of finger 13 is straight fora portion of-its length, rearward from the blade, and then curves to define arounded locking-headlt'at the end of the finger and V a reduced neckportion joining said locking I head to the straight portion of the-finger.

In contour,the rounded edge of said locking ansversely slightly beyond r the outer straight edge of the finger and head projects tr forms a forwardly directedcaniming' surface and a rearwardly directed camming surface. 'At the juncture of theshank with the body of the blade the latter is widened slightly and formed with inclined stop shoulders15 for abutting the shoulders 8 of the handle.

' The spring. fingers '12 and 13 ofthe'blade shank, when free, are expanded slightly so' that the width of the shank is slightly greater than that of the socket. In sliding the shank into the socket. the spring fingers are compressed slightly by forcing their rounded ends against the flaring shoulders 8 at the socket entrance. When the shank is inserted far enough to bring the blade shoulders 15 against the'shoulders 8 the. lockinghead 1 1 enters clearance cavity 5 and snaps into locking en gagement with one of the concave locking spring fingers is only'partly relieved by the snapping of the locking head into locking position. Therefore the fingers will continue the socket. There is also a snug fit between the flat opposite side faces of the shank and the flat sidewalls of the socket which combined' with the expanding tendency of the spring fingers and th'e'abutment'of the shoulders '8jand15 causes the blad e'to be firmly held against wabbling in any direction. "Slot 110 extends inward. to a point adjacent the shoulders 15 so that the blade shank is compressible and resilient for substantially/its entire length, for good holding engagement with the handle socket. Y I i The handle cleft 7and the slot 10 ofthe inserted blade are in register and in orderto remove the blade it is only requiredjto insert aconvenient tool into the slot and forcibly withdraw the shank from the socket, the rounded locking head being cammed over the rounded locking shoulder which it engages. Furthermore the cleft and slot render the knife lighter at the uncture of the blade and the handle and give the knife a good balance.

The design of the knifeprovides for-the reversal of the blade shank in the handle socket. This is a most desirable feature in a surgical knife. The handle and its socket 2 are symmetrical'about a horizontal axis and are designed for the ready attachment of the blade with its edge facing in eitherdirection. No particular carev is required 011 the part of the surgeon or his attendant in attaching the blade. The blade shank is merely thrust forcibly into the socket and automatically locked without the necessity of registering cooperating locking means upon the shank and handle. Since the socket 3 is symmetrical it provides clearance and locking engagement for the shank when the 7 later is inserted, as shown in Fig. 3, or when blades after a single use.

it is inserted in a transversely reversed position, as shown in Fig. 4. The locking head 14 is located upon the same side as the knife edge. Consequently in both positions of the knife blade pressure upon the edge of the blade tendsto rock the locking head in a direction to make a more secure locking engagement. The blade is of a thin, inexpensive type and it is the custom to discard-such My invention facilitates the removal of the blades and their replacement bynew ones and avoids all possibility of improper setting of the blades in the handle. The surgeon is, therefore, as sured of receiving the knife with its blade properly adjusted. The knife is entirely free of screws, pins and projecting parts. Its structure is extremely simple and its surfaces are smooth so that it may be easily kept clean and sanitary. o

What I claim is:

1. A' surgical knife comprising a blade integrally formed with a flat shank in the plane of the blade and longitudinally bi-- furcated to form two fiexibleand resilient fingers; a locking projection integrally formed on one of said fingers at a point spaced materially from the blade and pro-- jecting, transversely outward from the outer ongitudinal edge of the finger and having camming surfaces at the forward and rear edges thereof; a handle formed atone end with a flat shank-receiving socket defining an entrance passage of less width than the expanded shank and locking projection and laterally extended to form locking shoulders extending transversely outward from the opposite longitudinal edges of said passage near the inner end thereof, the shank fingers being compressible toward each other in the plane ofthe shank and. blade for endwise insertion of the shank into the socket and expansible to snap the locking projection into yieldable locking engagement with either of said locking shoulders, the handle, shank and locking projection being formed to cooperate for the insertion and locking of the shank in transversely reversed positions and for the withdrawal of the shank by an outward pull upon the blade through an implement inserted in shank bifurcation, and the handle cross section extending outward beyond the inserted locking projection in both of its locked positions to shield the locking projection from contact with the hand of the user of the knife.

2. A surgical knife comprising a blade integrally formed with a flat, transversely compressible and resilient shank in the plane of the blade; a locking projection formed upon the shank at a point spaced from the blade and projecting transversely outwardof said passage near the inner end of the latter, the shank being compressible in the plane of the shank and blade for endwise insertion of the shank into the socket andexpansible to snap the locking projection into yieldable locking engagement with either of said locking shoulders, the handle, shank and locking, projection being formed to cooperate for the insertion and locking of the shank in transversely reversed positions and for the withdrawal of the shank by an outward pullupon the blade, and the handle cross section extending outward beyond the inserted looking projection in both of its locked positions to shield the locking projection from contact with the hand of the user of the knife.

8. A surgical knife comprising a blade integrally formed with a fiat shank in the plane of the blade and longitudinally bifurcated to form two flexible and resilient fingers; a

locking projection integrally formed on one of said fingers at a point materially spaced from the blade and projecting transversely outwardfrom one ofthe outer longitudinal edges of the finger and having camming surfaces at the forward and rear edges thereof;

a handle formed at one end with a fiatshankreceiving socket defining an entrance passage of less width than the expanded shank and locking projection and laterally extended near the inner end thereof to form locking shoulders extending transversely outward from'the opposite longitudinal edges of said passage, the shank fingers being compressible toward each other in the plane of the shank and blade for endwise insertion of the shank into the socket and expansible to snap the locking projection into releasable locking engagement with either of said locking shoulders, the handle, shank and lockin projection being formed to cooperate for t e in sertion and locking of the shank in transversely reversed positions.

4. A surgical knife blade of stamped sheet metal of uniform thickness and having parallel side faces and integrally formed with a flat shank in the plane of the blade, said shank being longitudinally bifurcated to form two flexible and resilient fingers, the blade and the fingers being of the same thickness; a

pressible'edgewise throughout substantially I its entire length.

In testimony whereof I hereunto afiix'my signature.

ALEXANDER A. S. STUART, 

